Safety harness



Aug. 31, 1965 A. H. MOFARLANE ETAL SAFETY HARNESS 2 Sheets-Sheet 1 FiledNov. 14, 1962 1965 A. H. MOF'ARLANE ETAL 3,203,541

SAFETY HARNESS 2 Sheets-Sheet 2 United States Patent 3,203,641 SAFETYHARNESS Arthur Herbert McFarlane, Basildon, Essex, and Eric HerbertSponge, Harold Hill, Essex, England, assignors, by mesne assignments, toPacific Scientific Company, 'San Francisco, Calif, a corporation ofCalifornia Filed Nov. '14, 1962, Ser. No. 237,462

Claims priority, application Great Britain, Nov. 15, 1961, 40,201/61;July 27, 1962, 28,984/62; Aug. 27, 1962, 32,899/62 2 Claims. (Cl.242-1014) This invention relates to a safety harness for use bytravellers seated or otherwise supported in road and rail vehicles, airand marine craft, and in general to harness reels of the type comprisinga casing to be fixed, in a suitable position, to the floor or frame ofthe vehicle or craft, in which casing a spindle is mounted to turn, towhich one end of a strap is fixed, and in which the strap is adaptedautomatically to be wound into the casing and onto the spindle 'by acoiled spring of a desired number of turns, one end of which is securedto the spindle and the other to the casing, and unwound from the spindleby pulling on the other end of the strap which passes to the exteriorthrough an opening in the casing, and is detachably or otherwiseconnected to the harness.

The invention is particularly concerned with harness reels of the abovegeneral type and of the further type which includes inertia lockingmeans, comprised by an inertia mass so mounted in the casing that whenthe strap is pulled out from the casing relatively slowly (which happensby the normal movements of the traveller) it participates in such slowmovement, but which when there is a sudden pull on the strap (by thesudden deceleration of the vehicle which tends relatively to throw thetraveller wearing the harness forwards, laterally or otherwise) then themounting of the inertia mass is such that its inertia instantly causesit to lag behind and not to participiate in the sudden pull, and by suchlagging action to operate associated brake or locking means to hold thestrap from further unwinding movement; in the result the harness holdsthe traveller from being thrown forwards, laterally, or otherwise.

In such a construction it is known to provide at the end of the spindleremote from the coiled spiral spring, a member made integral with thespindle, having a surface of revolution about the axis of the spindleformed with a cam and in which there is provided an inertia mass ofgeneral cylindrical form coaxial with and mounted to turn in relation tothe spindle, a surface of which is adjacent the cam and shaped toco-operate therewith in the manner of a cam follower spring means of alight nature being provided to hold the inertia mass in contact with thecam with slight force so that said mass is caused to turn with thespindle during the slow movements of the strap, together with lockingmeans carried by the inertia mass adapted to be brought into engagementwith co-operating locking means in fixed relation with the casing sothat when, by its inertia to sudden movement, the said mass overcomesthe slight force of the spring and ceases to turn with the spindle, itrelatively moves over the cam, the shape of which then causes the saidmass to move axially further away from the member with the cam to causethe locking means of the said mass to engage the fixed locking means ofthe casing and hold the strap locked in position.

The present invention provides an inertia operated safety harness havinga reel, an inertia member adjacent said reel and mounted both formovement therewith and relative movement with respect thereto and meansfor locking said reel against rotation in the pay-out direction onoccurrence of said relative movement wherein inertia-member-restrainingmeans are provided which are operatively engageable with said inertiamember to restrain movement thereof with said reel whereby said reel isimmediately locked when moved in the pay-out direction, or itssensitivity varied.

Referring to the drawings filed herewith wherein similar characters ofreference are used to designate corresponding parts:

FIG. 1 is a view mainly in section of one form of harness reel made inaccordance with the present invention.

FIG. 2 is a View from the left of FIG. 1.

FIG. 3 is a view generally on the line 3--3 of FIG. 1.

FIG. 4 is a view similar to FIG. 3 of a modified gravity sensitivemeans.

FIG. 5 is a diagrammatic longitudinal section of one form of safetyharness made in accordance with the present invention which is adaptedto be mounted behind a seat either on the seat frame or on the floor.

FIG. 6 is a view from the right of FIG. 5, the bottom part being cutaway to show a section on the line VIVI of FIG. 5.

FIG. 7 is a detail plan view of the inertia member shown in FIGS. 5 and6.

In the example shown in FIGS. 1 to 3 the reel comprises central casing11 providing an entrance tunnel 12 and a reel housing 13. The sides ofthe reel housing 13 are apertured and bearing sleeves 14 for the reelspindle 15 line the apertures. The bearing sleeves 14 are backed byannular members 16 fitted onto flanges 17 formed integrally with thecasing 11. A strap 19 shown in dotdash lines in the drawings, passesonto the reel housing 13 through the tunnel 12 and is wound onto thespindle 15 constituting the inertia operated safety harness reel. Thespindle 15 carries two guide discs 18 positioned on each side of thewound strap to guide the strap as it is wound up. The right hand end, asseen in FIG. 1, of the reel spindle 15 projects into an end housing 21and is encircled by a helical spring 22. This spring 22 acts between thespindle 15 and the end housing 21 and is preloaded to wind the strapinto the reel housing 13.

The other end of the spindle 15 projects into an end housing 23 andcarries a thrust plate 24 which is fast with the spindle 15. The thrustplate 24 has three equal spaced recesses 25 in it which provide seatsfor three ball bearings 26. Beyond the thrust plate 24 the spindle 15carries a bearing sleeve 27 on which an inertia plate 28 ofsubstantially cylindrical shape is mounted, said plate constituting theinertia member associated with the reel. The plate 28 is free to rotateabout the spindle 15. The inertia plate 28 has three equally spacedrecesses 29 in it. These recesses 29 have the entrance shape shown inFIG. 3 and together with balls 26 serve as jamming means as will furtherappear. The inertia plate is urged by a light spring 31 away from afriction pad or locking member 32.

In the use of the reel, when a steady slow pull is exerted on the strap,the inertia plate 28 is carried round with the thrust plate 24. However,on a sudden increase in tension of the strap, the thrust plate 24accelerates rapidly. This acceleration is not instantly followed by theinertia plate 23 and that plate lags behind the plate 24. Due to theshape of the recesses 29, the ball bearings 26 force or jam the inertiaplate 28 axially away from the thrust plate 24 and into contact with thefriction pad 32. Rotation of the inertia plate 28 is therefore resistedcausing the ball bearing 26 to ride further along the recesses 29. Theinertia plate 28 is therefore forced more firmly into contact with thefriction pad 32. The reel is therefore locked to the friction pad andwinding out of the strap is prevented. Instead of a friction pad lockingmeans may be provided such as a pawl and ratchet.

In the harness reel modified to embody the present invention, the reelhousing 33 is enlarged to accommodate a pawl or sear pivotally mountedon a pintle 34, said pawl or sear 33 constituting theinertia-memberrestraining means and is a second inertia member. The pawl33 has a projecting portion or holding finger 35 shaped to fit againstthe inertia plate 28. The finger 35 may have a friction surface. Theouter end of the pawl 33 is formed as a counterweight 36. Thecounterweight 36 is arranged to hold the finger 35 away from the inertiaplate 28 during steady horizontal movement of the reel.

Consider now that the foregoing inertia reel is fitted in an aircraft.During manoeuvring of the aircraft, circumstances can arise in which theinertia reel does not lock but a person on the seat undergoes forwardmovement relative to the scat. These circumstances may arise in a dive.During a steady dive or on deceleration, the pawl or sear swings undergravity and contacts the inertia plate 23. The contact may be very lightbut it is sufficient to cause a lag of the inertia plate 28 relative tothe thrust plate 24. The ball bearings 26 therefore ride along therecesses 29 and act to force the inertia plate 28 against the frictionpad 32. The movement of the ball bearings 26 along the recesses 25? isprogressive and continues until the reel is locked.

In the construction shown in FIG. 4 it will be seen that the pawl 33 isprovided with two fingers 35 and 35' respectively. In this arrangementthe counter-weight 36 is still arranged to hold the finger 35 and thefinger 35' away from the inertia plate 28 during steady horizontalmovement of the reel. During a dive or on deceleration the pawl or sear33 either under the force of gravity or of its inertia duringdeceleration causes the finger 35 to contact the inertia plate 28. Inaddition, with the construction shown in FIG. 4 movement of the inertiaplate 28 will also be inhibited during a climb or on acceleration andmoreover the device would operate if the aircraft were rolled onto itsback because in that event the counter-weight 36 would tend to falleither side of the centre line passing through the pintle 34, so thatone or other of the fingers 35 or 35' would be caused to engage theinertia plate 28 and inhibit its movement. It will also be appreciatedthat this arrangement can be used equally well in connection with abackward facing seat as for a forward facing seat, whereas theconstruction shown in FIG. 3 will only work in one condition.

The provision of a pawl or sear as described above, by engaging andrestraining rotation of the inertia member positively ensures locking ofthe reel during any abnormal condition of an aircraft to which the reelis fitted which affects said second inertia member including forces ofgravity.

Turning now to FIGS. 5 to 7 of the drawings which show an inertiaoperated safety harness reel similar to that shown in FIGS. 1 to 3, thereel housing 13 is enlarged to accommodate a pawl or sear constitutingthe inertiamember-restraining means.

Instead of this pawl being mounted on a single pintle as described aboveand arranged to be moved into the restraining position on accelerationor deceleration or when the vehicle is tilted up or down in a forwarddirection the sear shown is gimbal mounted as hereinafter described andhas two pairs of oppositely arranged arms 49 and 42 radiating from acommon hub 44. The hub 44- is mounted in a ring 46 on pivot 48 said ringitself being mounted on pintles 50 in the housing 23 so that the pin 43and pintles 50 constitute a gimbal mounting. Extending downwardly fromthe hub 44 is a bob weight 52. The inertia member 28 in this arrangementis provided with teeth 54 adapted to be engaged by any one or more ofthe arms 42 or 44 according to which way the bob weight 52 swings thesear 33. It will be seen that this gimbal arrangement provides a moreadvantageous arrangement than that shown above since it is sensitive toforces due to gravity or changes in velocity acting thereon in anydirection. In operation when the bob weight 52 is displaced by any suchforce one or other of the teeth of the arms 40 or 42 will engage theteeth 54 and by restraining the inertia member 23 against rotation willassist the action of the inertia member 23 to cause the reel spindle tobe locked.

What We claim and desire to secure by Letters Patent is:

1. An inertia operated safety harness for vehicles including aircraftcomprising, a housing, a spindle rotatably carried by said housing, aharness reel fixed on said spindle, a flexible connector adapted to beattached to a seat occupants harness and extending into said housing forconnection to said reel to be wound thereupon, spring means within saidhousing connected to said spindle for winding the flexible connectoronto the said harness reel to apply a slight tension on the flexibleconnector and on the seat occupants harness while allowing free normalmovements of the occupant in use, a substantially cylindrically surfacedinertia member positioned adjacent said reel and mounted on said spindleboth for rotational movement with said reel and relative longitudinaland rotational movement with respect thereto, a locking member fixedlycarried by said housing opposite said inertia member, inertia membercamming means comprising balls within said housing interposed betweensaid reel and said inertia member for urging said inertia member againstsaid locking member for locking the inertia member and said reel againstrotation in the pay-out direction on occurrence of said relativerotational movement due to acceleration movement of said flexibleconnector exceeding a predetermined value, and a second inertia membercomprising a pendulous mass pivoted on said housing and having aprojecting portion positioned adjacent said cylindrically surfacedinertia member and responsive to acceleration and deceleration of thevehicle exceeding a predetermined value to cause said projecting portionto grippingly engage the cylindrical surface of said first-named inertiamember to thereby operate to restrain rotational movement of saidfirst-named inertia member with respect to said reel, whereby anymovement of said reel in the pay-out direction thereafter due tomovement of the seat occupant brings the locking means for thefirst-named inertia member into operation to lock the reel and hold theseat occupant in his seat.

2. An inertia operated safety harness for vehicles including aircraftcomprising, a housing, a spindle rotatable within said housing, aharness reel fixed on said spindle to rotate therewith, a flexibleconnector adapted to be attached to a seat occupants harness andextending into said housing for connection to said reel to be woundthereupon, spring means within said housing connected to said spindlefor winding the flexible connector onto the said harness reel to apply aslight tension on the flexible connector and on the seat occupantsharness while allowing free normal movements of the occupant in use, athrust plate fixed on said spindle, a substantially cylindrical inertiamember having a substantially cylindrical outer surface and turnablymounted on said spindle, jamming means interposed between said thrustplate and said inertia memher, a locking member attached to said housingin opposed relation to said inertia member and spring means for normallyholding said locking member and said inertia member apart, said inertiamember acting upon the movement of said flexible connector outwardly ofsaid housing at an excessive rate of acceleration determined by the massof said inertia member and the force of said spring means, incooperation with said jamming means to overcome said spring means andbind said inertia member against said locking member, thereby stoppingthe outward movement of said flexible connector and retaining theoccupant in his seat, and a second inertia member comprising a bobweight suspended from a pivotal support on said casing,

5 6 said second inertia member having projecting finger means ReferencesCited by the Examiner and being movable 1n response to excess veacceleration UNITED STATES PATENTS and deceleration movements of saidvehicle determined by the physical proportions of said bob weight toengage 2,650,655 9/ 53 w et a1 242-1074 X 2,708,966 5/55 Dav1s 242107.4

the cylindrical outer surface of said first inertia member 5 to effectthe binding of said first inertia member against 3,058,687 10/62 saidlocking member upon movement of the seat occupant 3,122,338 2/64Whlttmgham 242 107-4 and said flexible connector to thereby also sto theout- Ward movement of said flexible connector and retaining the MERVINSTEIN Pnmary Examiner occupant in his seat responsive to such excessivevehicle 10 DONALD W. PARKER, Examiner. movements.

1. AN INERTIA OPERATED SAFETY HARNESS FOR VEHICLES INCLUDING AIRCRAFTCOMPRISING, A HOUSING, A SPINDLE ROTATABLY CARRIED BY SAID HOUSING, AHARNESS REEL FIXED ON SAID SPINDLE, A FLEXIBLE CONNECTOR ADAPTED TO BEATTACHED TO A SEAT OCCUPANT''S HARNESS AND EXTENDING INTO SAID HOUSINGFOR CONNECTION TO SAID REEL TO BE WOUND THEREUPON, SPRING MEANS WITHINSAID HOUSING CONNECTED TO SAID SPINDLE FOR WINDING THEFLEIBLE CONNECTORONTO THE SAID HARNESS REEL TO APPLY A SLIGHT TENSION ON THE FLEXIBLECONNECTOR AND ON THE SEAT OCCUPANT''S HARNESS WHLE ALLOWING FREE NORMALMOVEMENTS OF THE OCCUPANT INUSE, A SUNSTANTIALLY CYLINDRICALLY SURFACEDINERTIA MEMBER POSITIONED ADJACENT SAID REEL AND MOUNTED ON SAID SPINDLEBOTH FOR ROTATIONAL MOVEMENT WITH SAID REEL RELATIVE LONGITUDINAL ANDROTATIONAL MOVEMENT WITH RESPECT THERETO, A LOCKING MEMBER FIXEDLYCARRIED BY SAID HOUSING OPPOSITE SAID INERTIA MEMBER, INERTIA MEMBERCANNING MEANS COMPRISING BALLS WITHIN SAID HOUSING INTERPOSED BETWEENSAID REEL AND SAID INERTIA MEMBER FOR URGING SAID INERTIA MEMBER AGAINSTSAID LOCKING MEMBER FOR LOCKING THE INERTIA MEMBER AND SAID REEL AGAINSTROTATION IN THE PAY-OUT DIRECTION ON OCCURRENCE OF SAID RELATIVEROTATIONAL MOVEMENT DUE TO ACCELERATION MOVEMENT OF SAID FLEXIBLECONNECTOR EXCEEDING A PREDETERMINED VALUE, AND A SECOND INERTIA MEMBERCOMPRISING A PENDULOUS MASS PIVOTED ON SAID HOUSING AND HAVING APROJECTING PORTION POSITIONED ADJACENT SAID CYLINDRICALLY SURFACEDINERTIA MEMBER AND RESPONSIVE TO ACCELERATION AND DECELERATION OF THEVEHICLE EXCEEDING A PREDETERMINED VALUE TO CAUSE SAID PROJECTING PORTIONTO GRIPPINGLY ENGAGE THE CYLINDRICAL SURFACES OF SAID FIRS-NAMED INERTIAMEMBER TO THEREBY OPERATE TO RESTRAIN ROTATIONAL MOVEMENT OF SAIDFIRST-NAMED INERTIA MEMBER WITH RESPECT TO SAID REEL, WHEREBY ANYMOVEMENT OF SAID REEL IN THE PAY-OUT DIRECTION THEREAFTER DUE TOMOVEMENT OF THE SEAT OCCUPANT BRINGS THE LOCKING MEANS FOR THEFIRST-NAMED INERTIA MEMBER INTO OPERATION TO LOCK THE REEL AND HOLD THESEAT OCCUPANT IN HIS SEAT.